The disclosure relates to a hydraulic fan drive for a cooling system of an internal combustion engine.
DE 43 21 637 A1 discloses a hydraulic fan drive for a cooling system of an internal combustion engine. The fan drive has a variable-displacement pump driven by the internal combustion engine, and a constant-displacement motor which drives a fan wheel. In this case, the variable-displacement pump is regulated by an actuating cylinder and by a valve which corresponds to a load-sensing regulating valve. A control pressure can be generated with the aid of a nozzle and a proportionally adjustable pressure-limiting valve from the pumping pressure prevailing in the connecting line between the variable-displacement pump and the constant-displacement motor.
DE 43 21 636 A1 shows a comparable hydraulic fan drive, comprising a variable-displacement pump driven by an internal combustion engine and comprising a constant-displacement motor which drives a fan wheel. During a switching-on time of a starter motor of the internal combustion engine, the variable-displacement pump is briefly set to a small delivery quantity or to a zero delivery quantity in order to reduce the load and the driving torque of the starter motor.
A disadvantage of hydraulic fan drives of this type is that load peaks of the internal combustion engine that may arise during the operation thereof, for example because of a plurality of supplied consumers, are increased even further by the connected fan drive.
By contrast, the disclosure is based on the object of providing a hydraulic fan drive for an internal combustion engine, said fan drive reducing load peaks of the internal combustion engine.